Sahih Muslim Book 31, Hadith Number 6031.

Chapter : The merits of Ubayy b Ka’b and a group of Ansar (Allah be pleased with them).

Anas b. Malik reported that Allah’s Messenger (may peace be upon him) said to Ubayy: Verily Allah, the Exalted and Glorious, has commanded me to recite the Qur’an to you, whereupon he said: (Has) Allah mentioned my name to you? He said: Allah has mentioned your name to me. Thereupon he began to shed tears (of joy)